Chinese phone maker Huawei is under investigation by the US Department of Justice, the Wall Street Journal reports. The investigation aims to determine whether Huawei violated US sanctions against Iran. It's not clear what stage the investigation is in or exactly what allegations have been presented.

This isn't the first time Huawei has been under the government's microscope. Huawei's relationship with the US in recent years has been in nearly constant turmoil. Heads of the CIA, FBI and NSA all warned consumers against purchasing Huawei phones in an open Congressional testimony in February, citing security concerns.